Effect of Tillage and Fertilization Practices on Soil Physical Properties and Grain Yield in the Tableland Region of China’s Loess Plateau

Water scarcity, poor soil, and low water and fertilizer utilization are major challenges on agricultural production in the tableland region of China’s Loess Plateau. Optimizing tillage patterns and improving soil nutrient status can improve crop yield and water and fertilizer utilization efficiency. A field trial was initiated in 2005 to assess the impacts of various tillage and fertilization practices on dryland agricultural production. A split-plot design was used, with tillage practices (traditional tillage and no tillage) as the main plot treatment and fertilization management (no fertilization (CK), mineral nitrogen (N), mineral phosphorus (P), composted cow manure (M), a combination of mineral nitrogen and phosphorus (NP), and a combination of mineral nitrogen, phosphorus, and composted cow manure (NMP)) as the split-plot treatment. An experiment was conducted from 2022 to 2024. The NMP treatment resulted in lower bulk density, a lower three-soil-phase index, and higher mean weight diameter, geometric mean diameter, soil water storage, total nitrogen, and soil organic matter than the CK. In the no-tillage treatment, the crop roots were less effective at extracting water from the deep subsoil, leading to greater residual moisture at depth (especially in the 120–200 cm soil layer) and lower yield and water use efficiency than in traditional tillage. The grain yield and water use efficiency were 9.2% and 8.4% lower, respectively, under no tillage than under traditional tillage. The NMP under traditional tillage exhibited lower surface soil bulk density and a higher three-soil-phase index, mean weight diameter, geometric mean diameter, soil organic matter, total nitrogen, and water use efficiency than the unfertilized control, resulting in higher grain yields. The NMP under traditional tillage is recommended to increase grain yield and water use efficiency in wheat–maize rotation systems in the tableland region of China’s Loess Plateau. Future studies should analyze the deep root architecture and the effect of weed competition on soil water depletion.